Wind propelled vehicles having a body means, which may be, e.g., a surf board, adapted to support a user, and a pivotally attached wind propulsion means mounted on a spar attached to the vehicle by, e.g., a universal joint, and having a pair of curved booms athwart the spar to contain the sail and provide a hand hold for the user of the vehicle, are well known in the art as shown in the patent to Schweitzer et al, U.S. Pat. No. 3,487,800.
In the past, it has been common to attach the spar ends of the booms to the spar by a reinforced tape which is attached to each boom and runs on either side of the spar to engage the spar in a pocket formed between the tape extending across the forward part of the spar and the tape extending across the aft part of the spar. In addition, the juncture of the two booms has been formed with an attached D-ring through which a lashing line can be passed to lash the booms to the spar. Further, as shown in the article by Cullin Terry entitled Windsurfer Booms appearing at page 8 of Windsurfer Magazine, Volume 9, Number 2, Fall 1979, shows a boom fitting having a pair of cylindrical boom receiving members each having an open end and a closed end, with the closed ends joined by a generally D-shaped thin connecting member having a large centrally located lashing line passage and a smaller and off center lashing line passage aligned with the longitudinal axis of one of the boom receiving members, and with that some boom receiving member having a jam cleat extending longitudinally outward from the outer surface thereof. In operation, this boom fitting is attached to the spar by a lashing line which is made fast at one end to the spar and passed through the large centrally located line passage, looped around the spar and passed through the smaller line passage and into the jam cleat, with the boom fitting being tightened to the spar by pulling the lashing line through the jam cleat to pull the spar as tightly as possible between the boom receiving members. This boom fitting shown in the prior art is constructed of a molded plastic including the region where the spar contacts the outer surfaces of the boom receiving members when the boom fitting is tightened to the spar. In operation, since the booms provide a hand hold means for the user of the vehicle, and a means for setting the angle of attack of sail to the wind direction, the boom fitting will rotate about the spar and at the same time the spar will tend to slide along the surface of the boom receiving member so that the boom fitting becomes cocked on the spar. This effect is even more pronounced in the prior art method and apparatus for attaching the booms to the spar shown in the patent to Schweitzer noted above.
The present invention relates to a boom fitting which is more easily tightenable through the use of a lashing line and which has the surfaces of the boom receiving members which contact the spar coated with a resilient foam material, e.g., polyurethane foam with a texturized outer surface to reduce or eliminate the tendency of the booms to become cocked on the spar. More particularly, the present invention relates to a spar-end boom fitting comprising a first and a second boom receiving member each having a boom receiving bore therein and each being joined by a connecting member, with the connecting member forming with the boom receiving members a spar receiving indentation, and with the connecting member having a first and second lashing line passage therethrough. A jam cleat is formed radially along the outer circumference of one of the boom receiving members, including a groove, having a pair of opposed rows of teeth. Further, the spar receiving indentation is covered with a resilient foam material, e.g., polyurethane foam having a texturized outer surface, which will conform to the shape of the spar when the spar-end boom fitting is tightened to the spar.
In addition, the spar-end boom fitting of the present invention eliminates the need for knotting an up-haul line to a D-ring on the boom fittings of the prior art. The up-haul line is for assisting in erecting a fallen spar from the water when the user of the vehicle releases the boom allowing the spar and sail to fall into the water. The present invention provides an up-haul line passage through the connecting member which is tapered toward the center thereof and also a locking pin which fits into the tube-like center of the up-haul line and, in conjunction with the tapered surface of the up-haul line passage, locks the up-haul line within the passage.
Examples of the more important features of the present invention have thus been summarized rather broadly in order that the detailed description thereof that follows may be better understood, and in order that contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will also form the subject of the appended claims. These other features and advantages of the present invention will become more apparent with reference to the following detailed description of a preferred embodiment thereof in connection with the accompanying drawings, wherein the like reference numerals have been applied to like elements, in which: